We have initiated new research efforts in our clinical pharmacology project for the study of response modifiers on the clinical pharmacology of anticancer drugs. Hyperthermia dramatically alters the pharmacokinetics of cyclophosphamide and hopefully the clinical effects of this and other drugs. Dimethylsulfoxide neither alters the pharmacokinetics of cyclophosphamide nor the clinical response in patients with epidermoid carcinoma of the lung. Daunorubicin administered in repetitive doses in combination chemotherapy shows altered pharmacokinetics and disposition than that administered as single dosage.